Environment: `Node.js`.<br/>
[Ext Glob](https://github.com/micromatch/micromatch#extglobs): `/**/*.page.server.*([a-zA-Z0-9])`.

A `.page.server.js` file can export the following:
- `export { onBeforeRender }`
- `export { passToClient }`
- `export { render }`
- `export { prerender }`

The `.page.server.js` file is lazy-loaded: it is loaded only when needed which means that if no URL request were to match the page's route then `.page.server.js` is never loaded in our Node.js process' memory.

The `.page.server.js` file is always loaded & executed in Node.js.
